This invention relates to a power level setting/display circuit for setting and displaying the level of heating power of, for example, a microwave oven, more specifically to a power level setting/display circuit capable of displaying a set value of power level on a display unit in good conditions.
In a microwave oven with a digital display unit, the set heating time, selected temperature, and the power level are displayed on the display unit. The display register is of 4-digit configuration, and the power level is given by the first two digits (e.g., 0 to 99 max.), so that only the last two digits of the display register may be set for use when a function key for power level setting is operated. In changing a power level command "12" into "35," for example, the contents of the last two digits of the display register may be turned into "35" by successively depressing register keys "3" and "5." In changing a power level command "12" into "5," however, the higher-place digit "1" is erased and "5" is placed as the bottom digit by depressing the register key "5" as it is, leaving the figure "2," which has previously been in the bottom place, in the second lowest place. In such case, therefore, power level setting must be executed anew after clearing all the contents of the display register by depressing a clear key or turning the power off and then on, according to the prior art system.